1. Field of the Invention
The invention relates to a solid electrolytic capacitor with anode and cathode terminals, and a method of manufacturing the solid electrolytic capacitor.
2. Description of Related Art
FIG. 11 is a sectional view of a conventional solid electrolytic capacitor. As shown in FIG. 11, the conventional solid electrolytic capacitor includes a capacitor element 100, an anode terminal 111, and a cathode terminal 112 that are buried in an exterior resin 120. The capacitor element 100 includes an anode body 101, an anode lead 102 implanted in the anode body 101, a dielectric layer 103 formed on a surface of the anode body 101, an electrolyte layer 104 formed on the dielectric layer 103, and a cathode layer 105 formed on the electrolyte layer 104.
Anode and cathode terminal surfaces 115 and 116 of the anode and cathode terminals 111 and 112 respectively are formed in a lower surface 120a of the exterior resin 120. A pillow member 114 is electrically connected with welding means such as laser welding to the surface of the anode terminal 111 opposite the anode terminal surface 115. A tip end portion 102a of the anode lead 102 of the capacitor element 100 is electrically connected to an end portion of the pillow member 114. The lower surface of the cathode layer 105 of the capacitor element 100 is electrically connected to the surface of the cathode terminal 112 opposite the cathode terminal surface 116.
In the conventional solid electrolytic capacitor, the ratio of volume of the capacitor element 100 to the solid electrolytic capacitor is low as the volume of the exterior resin 120 should be considered. Further, in the conventional solid electrolytic capacitor, only the lower surface of the tip end portion 102a of the anode lead 102 is connected to the pillow member 114, and only the lower surface of the cathode layer 105 of the capacitor element 100 is connected to the cathode terminal 112 as shown in FIG. 11. This reduces a contact area between the anode lead 102 and the pillow member 114, and a contact area between the cathode layer 105 and the cathode terminal 112, thereby increasing the ESR (equivalent series resistance) of the solid electrolytic capacitor.
In the solid electrolytic capacitor, an electrical path is formed between the anode and cathode terminal surfaces 115 and 116 through the capacitor element 100. The conventional solid electrolytic capacitor has a long electrical path between the anode and cathode terminal surfaces 115 and 116 as a result of a long distance therebetween, thereby increasing inductance between the anode and cathode terminal surfaces 115 and 116, namely the ESL (equivalent series inductance) of the solid electrolytic capacitor.